You don't need to party and drink crazy to feel like you're living. Just do stuff you enjoy, sports, hanging out with friends, restaurants, games and try some stuff you've never done (i'm not speaking about those crazy lifes experiences that you need to do once in a lifetime ^^). And you'll feel busy and you're gonna feel as if you're actually doing something of your life that you enjoy!
I think you're just in a depressed mood, that stuff happens to everyone once in a while. And trust me even the people that you think are having a good life are going trough this phase at some point too.You should reflect on your life and change what you don't like about it. If you don't enjoy something in your life, change it now, those depressing moments happens because of something specific once you find that out and solve it, you'll feel better.
About settling down, i do think you're young but it all depends on the person, if you really feel like settling down with someone you like go ahead but like earthforge mentionned it , it might get hard economically speaking and so on.. But if you want it real bad, then try it. What's the worst that's going to happen? You can always go back to your old life if it doesnt go well with the girlfriend and the house but that depends again on some conditions ( if you used to live with your parents etc..)
The best advice we all could give you is, think about what's wrong in your life and try to solve that problem. I can't really know what you're going trough right now but you seem really lonely, just try to bond with some people or go talk to your friends, go socialize again and you might try some community services in order to bond with people so you could feel less lonely. If you can't or don't want to talk about it with your friends, try someone you actually don't know well (someone who won't judge you) Maybe when you say you miss doing things with someone, you're just feeling lonely and not necessarily hoping to get a new partner (but then again i'm not in your body

).
Anyways, I hope you're gonna feel better soon buddy

! But I'm really curious to know what 's your definition of ''wild life'', could you describe it?